Name:	fhlbd_FinancingReceivableNetDeferredLoanCosts
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Reflects the cumulative amount of discounts from the face amount of loans that are being amortized into income as an adjustment of yield

No definition available.

Name:	fhlbd_FinancingReceivableUnamortizedDiscounts
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Reflects the cumulative amount of premiums over the face amount of loans that are being amortized into income as an adjustment to yield

No definition available.

Name:	fhlbd_FinancingReceivableUnamortizedPremiums
Namespace Prefix:	fhlbd_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Mortgage Loans On Real Estate, Original Contractual Terms, Medium-Term Loan

No definition available.

Name:	fhlbd_MortgageLoansOnRealEstateOriginalContractualTermsMediumTermLoan
Namespace Prefix:	fhlbd_
Data Type:	xbrli:integerItemType
Balance Type:	na
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- References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G)(Footnote 3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478322/948-310-S50-2

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column G))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column C))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 5: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column B))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 6: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column A)(Footnote 3))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 7: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column H))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 8: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column F))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 9: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column E))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 10: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column D))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 11: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column A)(Footnote 4))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Reference 12: http://www.xbrl.org/2003/role/disclosureRef
-Topic 948
-SubTopic 310
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.12-29(Column A)(Footnote 2))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479628/948-310-S99-1

Name:	srt_MortgageLoansOnRealEstateLineItems
Namespace Prefix:	srt_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount, after allowance for credit loss, of accrued interest on financing receivable.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-5

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3A
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3A

Name:	us-gaap_FinancingReceivableAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

Name:	us-gaap_FinancingReceivableAllowanceForCreditLossExcludingAccruedInterest
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

Amortized cost excluding accrued interest, after allowance for credit loss, of financing receivable. Excludes net investment in lease.

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestAfterAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amortized cost excluding accrued interest, before allowance for credit loss, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479344/326-20-45-1

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3B
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-3B

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479319/326-20-50-5

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Amortized cost excluding accrued interest, before allowance for credit loss, fee, and loan in process, of financing receivable. Excludes net investment in lease.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 942
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(7))
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478546/942-210-S99-1

Name:	us-gaap_FinancingReceivableExcludingAccruedInterestBeforeAllowanceForCreditLossFeeAndLoanInProcess
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=us-gaap_ConventionalLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fhlbd_GovernmentLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=us-gaap_RealEstateLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	srt_MortgageLoansOnRealEstateDescriptionTypeOfPropertyAxis=srt_SingleFamilyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Name:	us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis=fhlbd_LoansReceivableWithFixedRatesOfInterestMediumTermMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: